Encapsulation film

ABSTRACT

An encapsulation film, an organic electronic device comprising the same, and a method for manufacturing an organic electronic device using the same are provided. The encapsulation film has excellent reliability that allows forming a structure capable of blocking moisture or oxygen flowing into an organic electronic device from the outside, absorbs and disperses the stress according to panel bending caused by CTE mismatch, and overcomes the performance decrease due to reliability degradation, while preventing generation of bright spots in the organic electronic device.

CROSS CITATION WITH RELATED APPLICATION(S)

This application is a National Stage Application of InternationalApplication No. PCT/KR2021/000014, filed on Jan. 4, 2021, which claimspriority to Korean Patent Application No. 10-2020-0000527 filed on Jan.2, 2020, the disclosures of which are incorporated herein by referencein their entirety.

FIELD

The present application relates to an encapsulation film, an organicelectronic device comprising the same, and a method for manufacturingthe organic electronic device.

BACKGROUND

An organic electronic device (OED) means a device comprising an organicmaterial layer that generates alternate current of charges using holesand electrons, and an example thereof may include a photovoltaic device,a rectifier, a transmitter and an organic light emitting diode (OLED),and the like.

The organic light emitting diode (OLED) among the above organicelectronic devices has less power consumption and faster response speedthan existing light sources, and is advantageous for thinning of adisplay device or illumination. In addition, the OLED has spatialusability and thus is expected to be applied in various fields coveringvarious portable devices, monitors, notebooks, and TVs.

In commercialization and application expansion of the OLED, the mostimportant problem is a durability problem. The organic materials and themetal electrodes, and the like included in the OLED are very easilyoxidized by external factors such as moisture. In addition, there isalso a problem that bright spots of the OLED are caused by the outgasthat may occur inside the OLED device. That is, products comprisingOLEDs are very sensitive to environmental factors. In addition, stressoccurs due to the bending of the panel at high temperatures, and thisstress makes the penetration of external moisture or oxygen easy.Accordingly, various methods have been proposed in order to suppress theoutgas generated inside, while effectively blocking penetration ofoxygen or moisture from the outside into an organic electronic devicesuch as OLED.

In order to solve such a problem, a thin film encapsulation process orthe like for preventing oxygen, moisture, and the like from flowing intothe OLED is required. As a material used in the conventional thin filmencapsulation process, glass or invar as a nickel-iron alloy, etc. havebeen used. However, glass has poor processability and invar as anickel-iron alloy is expensive and has a disadvantage of poor thermalconductivity, so that stainless steel (SUS) with high versatility thatcan solve such a disadvantage has attracted attention as a newencapsulant.

However, since stainless steel has a large difference in coefficient ofthermal expansion with the substrate, a difference in displacement withthe substrate occurs under high temperature conditions upon a bondingprocess or reliability evaluation, whereby there may be a problem thatthe moisture or oxygen blocking effect is lowered.

SUMMARY

The present application provides an encapsulation film having excellentreliability that allows forming a structure capable of blocking moistureor oxygen flowing into an organic electronic device from the outside,and absorbs and disperses the stress caused by panel bending, whilepreventing generation of bright spots in the organic electronic device.

The present application relates to an encapsulation film. Theencapsulation film can be applied to encapsulation layer orencapsulating an organic electronic device such as, for example, OLEDs.

Conventionally, a nickel-iron alloy (invar) has been commonly used as anencapsulation film, but the nickel-iron alloy has disadvantages that itis expensive, has poor thermal conductivity and has poor cutability. Thepresent application may provide an encapsulation film with excellentreliability at high temperatures that prevents the occurrence of brightspots in organic electronic devices, has excellent heat dissipationproperties, and absorbs and disperses the stress caused by panelbending, without using the nickel-iron alloy.

In this specification, the term “organic electronic device” means anarticle or device having a structure comprising an organic materiallayer that generates alternate current of charges using holes andelectrons between a pair of electrodes facing each other, and an examplethereof may include, but is not limited to, a photovoltaic device, arectifier, a transmitter and an organic light emitting diode (OLED), andthe like. In one example of the present application, the organicelectronic device may be an OLED.

An exemplary organic electronic device encapsulation film may comprisean encapsulation layer and a metal layer formed on the encapsulationlayer. The encapsulation layer may seal the top surface of the organicelectronic element formed on the substrate. The encapsulation layer mayalso comprise an encapsulation resin and a moisture adsorbent. Thecontent of the moisture adsorbent may be in a range such that γsatisfies 0.04 to 0.08 in the following general formula 1.Moisture adsorbent content=Q _(MAX)×(H _(T1) +H _(T2)×γ)H_(T1)  [General Formula 1]

In General Formula 1 above, Q_(MAX) is 60 to 90 parts by weight relativeto 100 parts by weight of the solid content of the encapsulation layer,H_(T1) is the thickness of the encapsulation layer at 25° C., H_(T2) isthe length of the encapsulation layer connecting the outermost side ofthe substrate and the outermost side of the metal layer at a temperatureof T2, T1 is 25° C., and T2 is 85° C.

In this specification, the term “thickness” may be an average thicknessor an average thickness of a side edge portion.

Although the encapsulation film is applied to encapsulate the topsurface of the organic electronic element formed on the substrate, thegeneral formula 1 and the general formulas 2 and 3 to be described belowdo not necessarily have to be measured in the substrate on which theorganic electronic element is formed, and the moisture adsorbent contentmay be measured in a state where the encapsulation film is attached onthe substrate. The metal layer may have, for example, a CTE range of 1.5times or more, 2 times to 5 times, 2.5 times to 4 times, or 2.8 times to3.5 times relative to the CTE of the substrate. After measuring thedimensional change according to temperatures using a Thermo-MechanicalAnalyzer (expansion mode, force 0.05N) with ASTM E 831 method, the “CTE(coefficient of thermal expansion)” means a value measured from thelength change curve of the encapsulation film according to thetemperature (−120 to 600° C.). The CTE may also be measured according toISO 11359-1 or ISO 11359-2.

In the present application, the encapsulation layer for encapsulatingthe top surface of the organic electronic element is disposed betweenthe substrate on which the element is formed and the metal layer.However, the substrate and the metal layer have different materials fromeach other, and thus also have different thermal expansioncharacteristics. When the encapsulation film or the organic electronicdevice is present at a high temperature for a certain period of time(when it is present in the process), a dimensional mismatch occursaccording to the difference in the degree of expansion between thesubstrate and the metal layer, where in the encapsulation layer betweenthe substrate and the metal layer, some peeling, gaps or voids occurdepending on the stress, resulting in a situation that external oxygenor moisture easily penetrates. By adjusting the moisture adsorbentcontent according to General Formula 1 above, the encapsulation layerabsorbs or disperses the stress well even between the substrate and themetal layer at high temperatures to prevent the occurrence of gaps orvoids on the side of the encapsulation layer, whereby the presentapplication can effectively prevent foreign substances from penetratingfrom the outside while having excellent moisture barrier properties.

In an embodiment of the present application, the encapsulation layer maysatisfy the following general formula 2.

$\begin{matrix}{\frac{H_{T2}}{H_{T1}} = {\frac{\sqrt{H_{T1}^{2} + {\Delta L_{CTE}^{2}}}}{H_{T1}} \leq 9.}} & {\left\lbrack {{General}{Formula}2} \right\rbrack}\end{matrix}$

In General Formula 2 above, H_(T1) and H_(T2) are as defined in GeneralFormula 1 above, and ΔL_(CTE) satisfies the following general formula 3.ΔL _(CTE)=(CTE _(METAL) −CTE _(SUB))×L _(T1)×(T2−T1)  [General Formula3]

In General Formula 3 above, CTE_(METAL) is the CTE value of the metallayer, CTE_(SUB) is the CTE value of the substrate, L_(T1) is the longside length of the encapsulation layer at room temperature, T1 is 25°C., and T2 is 85° C. All of General Formulas 1 to 3 above may bemeasured after applying the encapsulation film on the substrate, and maybe measured after substantially matching the long and short sides of theencapsulation film with the long and short sides of the substrate. Inthis specification, the substantial matching may have an error range of±5 μm, ±3 μm or ±1 μm. The ratio of H_(T1) and H_(T2) according toGeneral Formula 2 above may be in the range of 1 to 9, 2 to 8 or 3 to 7.By adjusting the ratio, the present application can implementdimensional reliability at high temperatures, moisture barrierproperties and high temperature endurance reliability together.

As described above, the encapsulation layer may comprise anencapsulation resin. The encapsulation resin may be a crosslinkableresin or a curable resin.

In one example, the encapsulation resin may have a glass transitiontemperature of less than 0° C., less than −10° C. or less than −30° C.,less than −50° C. or less than −60° C. The lower limit is notparticularly limited, which may be −150° C. or higher. Here, the glasstransition temperature may be a glass transition temperature aftercuring, and in one embodiment, it may mean a glass transitiontemperature after irradiating it with ultraviolet rays having anirradiance level of about 1 J/cm² or more; or a glass transitiontemperature after the ultraviolet irradiation and then furtherperforming thermosetting.

In one example, the encapsulation resin may comprise a styrene resin orelastomer, a polyolefin resin or elastomer, other elastomers, apolyoxyalkylene resin or elastomer, a polyester resin or elastomer, apolyvinyl chloride resin or elastomer, a polycarbonate resin orelastomer, a polyphenylene sulfide resin or elastomer, a mixture ofhydrocarbons, a polyamide resin or elastomer, an acrylate resin orelastomer, an epoxy resin or elastomer, a silicone resin or elastomer, afluorine resin or elastomer or a mixture thereof, and the like.

Here, as the styrene resin or elastomer, for example,styrene-ethylene-butadiene-styrene block copolymer (SEBS),styrene-isoprene-styrene block copolymer (SIS),acrylonitrile-butadiene-styrene block copolymer (ABS),acrylonitrile-styrene-acrylate block copolymer (ASA),styrene-butadiene-styrene block copolymer (SBS), styrene homopolymer ora mixture thereof can be exemplified. As the olefin resin or elastomer,for example, a high-density polyethylene resin or elastomer, alow-density polyethylene resin or elastomer, a polypropylene resin orelastomer or a mixture thereof can be exemplified. As the elastomer, forexample, an ester thermoplastic elastomer, an olefinic elastomer, asilicone elastomer, an acrylic elastomer or a mixture thereof, and thelike can be used. In particular, as the olefin thermoplastic elastomer,a polybutadiene resin or elastomer or a polyisobutylene resin orelastomer, and the like can be used. As the polyoxyalkylene resin orelastomer, for example, a polyoxymethylene resin or elastomer, apolyoxyethylene resin or elastomer or a mixture thereof, and the likecan be exemplified. As the polyester resin or elastomer, for example, apolyethylene terephthalate resin or elastomer, a polybutyleneterephthalate resin or elastomer or a mixture thereof, and the like canbe exemplified. As the polyvinyl chloride resin or elastomer, forexample, polyvinylidene chloride and the like can be exemplified. As themixture of hydrocarbons, for example, hexatriacotane or paraffin, andthe like can be exemplified. As the polyamide resin or elastomer, forexample, nylon and the like can be exemplified. As the acrylate resin orelastomer, for example, polybutyl(meth)acrylate and the like can beexemplified. As the epoxy resin or elastomer, for example, bisphenoltypes such as bisphenol A type, bisphenol F type, bisphenol S type and ahydrogenated product thereof; novolak types such as phenol novolak typeor cresol novolak type; nitrogen-containing cyclic types such astriglycidyl isocyanurate type or hydantoin type; alicyclic types;aliphatic types; aromatic types such as naphthalene type and biphenyltype; glycidyl types such as glycidyl ether type, glycidyl amine typeand glycidyl ester type; dicyclo types such as dicyclopentadiene type;ester types; ether ester types or a mixture thereof, and the like can beexemplified. As the silicone resin or elastomer, for example,polydimethylsiloxane and the like can be exemplified. In addition, asthe fluororesin or elastomer, a polytrifluoroethylene resin orelastomer, a polytetrafluoroethylene resin or elastomer, apolychlorotrifluoroethylene resin or elastomer, apolyhexafluoropropylene resin or elastomer, polyfluorinated vinylidene,polyfluorinated vinyl, polyfluorinated ethylene propylene or a mixturethereof, and the like can be exemplified.

The resins or elastomers listed above may be also used, for example, bybeing grafted with maleic anhydride or the like, by being copolymerizedwith other resins or elastomers through monomers for producing resins orelastomers, and by being modified with other compounds. An example ofother compounds above may include carboxyl-terminalbutadiene-acrylonitrile copolymers and the like.

In one example, the encapsulation layer may comprise, but is not limitedto, the olefinic elastomer, the silicone elastomer or the acrylicelastomer, and the like among the above-mentioned types as theencapsulation resin.

In one embodiment of the present disclosure, the encapsulation resin maybe an olefin-based resin. In one example, the olefin-based resin may bea homopolymer of a butylene monomer; a copolymer obtained bycopolymerizing a butylene monomer and another polymerizable monomer; areactive oligomer using a butylene monomer; or a mixture thereof. Thebutylene monomer may include, for example, 1-butene, 2-butene orisobutylene.

Other monomers polymerizable with the butylene monomers or derivativesmay include, for example, isoprene, styrene, or butadiene and the like.By using the copolymer, physical properties such as processability anddegree of cross-linking can be maintained and thus heat resistance ofthe adhesive itself can be secured when applied to organic electronicdevices.

In addition, the reactive oligomer using the butylene monomer maycomprise a butylene polymer having a reactive functional group. Theoligomer may have a weight average molecular weight ranging from 500 to5000 g/mol. Furthermore, the butylene polymer may be coupled to anotherpolymer having a reactive functional group. The other polymer may be,but is not limited to, alkyl (meth)acrylate. The reactive functionalgroup may be a hydroxyl group, a carboxyl group, an isocyanate group ora nitrogen-containing group. Also, the reactive oligomer and the otherpolymer may be cross-linked by a multifunctional cross-linking agent,and the multifunctional cross-linking agent may be at least one selectedfrom the group consisting of an isocyanate cross-linking agent, an epoxycross-linking agent, an aziridine cross-linking agent and a metalchelate cross-linking agent.

In one example, the encapsulation resin of the present application maycomprise a copolymer of a diene and an olefinic compound containing onecarbon-carbon double bond. Here, the olefinic compound may includebutylene or the like, and the diene may be a monomer capable ofpolymerizing with the olefinic compound, and may include, for example,isoprene or butadiene and the like. For example, the copolymer of anolefinic compound containing one carbon-carbon double bond and a dienemay be a butyl rubber.

In the encapsulation layer, the resin or elastomer component may have aweight average molecular weight (Mw) to an extent such that thepressure-sensitive adhesive composition can be formed into a film shape.For example, the resin or elastomer may have a weight average molecularweight of about 100,000 to 2,000,000 g/mol, 120,000 to 1,500,000 g/mol,or 150,000 to 1,000,000 g/mol or so. In this specification, the termweight average molecular weight means a value converted to standardpolystyrene measured by GPC (gel permeation chromatograph), and unlessotherwise specified, the unit is g/mol. However, the resin or elastomerdoes not necessarily have the above-mentioned weight average molecularweight. For example, in the case where the molecular weight of the resinor elastomer component is not in a level enough to form a film, aseparate binder resin may be blended into the pressure-sensitiveadhesive composition.

In another embodiment, the encapsulation resin according to the presentapplication may be a curable resin. When the encapsulation resin is acurable resin, the encapsulation resin may be a resin having a glasstransition temperature of 85° C. or more and 200° C. or less aftercuring. The glass transition temperature may be a glass transitiontemperature after photo-curing or thermosetting the encapsulation resin.The specific kind of the usable curable resin in the present disclosureis not particularly limited, and for example, various thermosetting orphoto-curable resins known in this field can be used. The term“thermosetting resin” means a resin that can be cured through anappropriate heat application or aging process, and the term“photo-curable resin” means a resin that can be cured by irradiationwith electromagnetic waves. Furthermore, the curable resin may be a dualcuring resin including both of heat curing properties and light curingproperties.

The specific kind of the curable resin in the present application is notparticularly limited as long as it has the above-mentionedcharacteristics. For example, it may be cured to exhibit an adhesiveproperty, which may include a resin containing one or more thermosettingfunctional groups such as a glycidyl group, an isocyanate group, ahydroxyl group, a carboxyl group or an amide group, or containing one ormore functional groups curable by irradiation with electromagneticwaves, such as an epoxide group, a cyclic ether group, a sulfide group,an acetal group or a lactone group. A specific example of such a resinmay include an acrylic resin, a polyester resin, an isocyanate resin oran epoxy resin, and the like, but is not limited thereto.

In the present application, as the curable resin, aromatic or aliphatic;or linear or branched epoxy resins may be used. In one embodiment of thepresent disclosure, an epoxy resin having an epoxy equivalent of 180g/eq to 1,000 g/eq, which contains two or more functional groups, may beused. By using the epoxy resin having an epoxy equivalent in the aboverange, characteristics such as adhesion performance and glass transitiontemperature of the cured product can be effectively maintained. Anexample of such an epoxy resin may include one or a mixture of two ormore of a cresol novolak epoxy resin, a bisphenol A type epoxy resin, abisphenol A type novolak epoxy resin, a phenol novolak epoxy resin, atetrafunctional epoxy resin, a biphenyl type epoxy resin, a triphenolmethane type epoxy resin, an alkyl-modified triphenol methane epoxyresin, a naphthalene type epoxy resin, a dicyclopentadiene type epoxyresin or a dicyclopentadiene-modified phenol type epoxy resin.

In the present application, as the curable resin, an epoxy resincomprising a cyclic structure in a molecular structure can be used, andan epoxy resin comprising an aromatic group (for example, a phenylgroup) can be used. When the epoxy resin comprises an aromatic group,the cured product has excellent thermal and chemical stability andsimultaneously exhibits a low moisture absorption amount, whereby thereliability of the organic electronic device encapsulation structure canbe improved. A specific example of the aromatic group-containing epoxyresin that can be used in the present disclosure may be one or a mixtureof two or more of a biphenyl type epoxy resin, a dicyclopentadiene typeepoxy resin, a naphthalene type epoxy resin, adicyclopentadiene-modified phenol type epoxy resin, a cresol-based epoxyresin, a bisphenol-based epoxy resin, a xylol-based epoxy resin, amultifunctional epoxy resin, a phenol novolak epoxy resin, a triphenolmethane type epoxy resin, and an alkyl-modified triphenol methane epoxyresin and the like, but is not limited thereto.

In one example, the encapsulation resin may be included in an amount of40 wt % or more, 45 wt % or more, 48 wt % or more, 50 wt % or more, 53wt % or more, 55 wt % or more, 58 wt % or more, 60 wt % or more, or 65wt % or more in the encapsulation layer, where the upper limit thereofmay be 90 wt % or less, 85 wt % or less, 83 wt % or less, 70 wt % orless, 65 wt % or less, 60 wt % or less, or 55 wt % or less. Theencapsulation resin has good moisture barrier properties, but has adisadvantage that heat resistance durability is lowered, so that byadjusting the content of the encapsulation resin, the presentapplication may maintain the heat resistance durability at hightemperature and high humidity together while sufficiently realizing themoisture barrier performance of the resin itself.

As described above, the encapsulation layer may comprise a moistureadsorbent. In this specification, the term “moisture adsorbent” may meana chemically reactive adsorbent capable of removing moisture orhumidity, for example, through chemical reaction with the moisture orhumidity that has penetrated the encapsulation film, as described below.

For example, the moisture adsorbent may be present, as the form ofparticles, in an evenly dispersed state in the encapsulation layer orthe encapsulation film. Here, the evenly dispersed state may mean astate where the moisture adsorbent is present at the same orsubstantially the same density even in any portion of the encapsulationlayer or the encapsulation film. The moisture adsorbent that can be usedin the above may include, for example, a metal oxide, a sulfate or anorganometallic oxide, and the like. Specifically, an example of thesulfate may include magnesium sulfate, sodium sulfate or nickel sulfate,and the like, and an example of the organometallic oxide may includealuminum oxide octylate and the like. Here, a specific example of themetal oxide may include phosphorus pentoxide (P₂O₅), lithium oxide(Li₂O), sodium oxide (Na₂O), barium oxide (BaO), calcium oxide (CaO) ormagnesium oxide (MgO), and the like, and an example of the metal saltmay include a sulfate such as lithium sulfate (Li₂SO₄), sodium sulfate(Na₂SO₄), calcium sulfate (CaSO₄), magnesium sulfate (MgSO₄), cobaltsulfate (CoSO₄), gallium sulfate (Ga₂(SO₄)₃), titanium sulfate(Ti(SO₄)₂) or nickel sulfate (NiSO₄), a metal halogenide such as calciumchloride (Ca Cl₂), magnesium chloride (MgCl₂), strontium chloride(SrCl₂), yttrium chloride (YCl₃), copper chloride (CuCl₂), cesiumfluoride (CsF), tantalum fluoride (TaF₅), niobium fluoride (NbF₅),lithium bromide (LiBr), calcium bromide (CaBr₂), cesium bromide (CeBr₃),selenium bromide (SeBr₄), vanadium bromide (VBr₃), magnesium bromide(MgBr₂), barium iodide (BaI₂) or magnesium iodide (MgI₂); or a metalchlorate such as barium perchlorate (Ba(ClO₄)₂) or magnesium perchlorate(Mg(ClO₄)₂), and the like, but is not limited thereto. As the moistureadsorbent which can be contained in the encapsulation layer, one or twoor more of the above-mentioned constitutions may be also used. In oneexample, when two or more are used as the moisture adsorbent, calcineddolomite and the like may be used.

Such a moisture adsorbent may be controlled to an appropriate sizedepending on the application. In one example, the average particlediameter of the moisture adsorbent may be controlled to 100 to 15000 nm,500 nm to 10000 nm, 800 nm to 8000 nm, 1 μm to 7 μm, 2 μm to 5 μm or 2.5μm to 4.5 μm. The moisture adsorbent having a size in the above range iseasy to store because the reaction rate with moisture is not too fast,does not damage the element to be encapsulated, and can effectivelyremove moisture without interfering with the hydrogen adsorption processin relation to a bright spot inhibitor to be described below. In thisspecification, the particle diameter may mean an average particlediameter, and may be one measured by a known method with a D50 particlesize analyzer, unless otherwise specified.

The content of the moisture adsorbent is not particularly limited, whichmay be appropriately selected in consideration of desired barrierproperties. The moisture adsorbent may be included in a range of 20 to200 parts by weight, 25 to 190 parts by weight, 30 to 180 parts byweight, 35 to 170 parts by weight, 40 to 160 parts by weight, or 45 to155 parts by weight relative to 100 parts by weight of the encapsulationresin. In addition, as will be described below, the encapsulation layerof the present application may further comprise a bright spot inhibitor,and the weight ratio of the bright spot inhibitor to the moistureadsorbent in the encapsulation film of the present application may be inthe range of 0.05 to 0.8 or 0.1 to 0.7. In the present application, thebright spot inhibitor is dispersed in the film to prevent bright spots,but the bright spot inhibitor added to prevent the bright spots may beincluded in a specific content ratio with the moisture adsorbent,considering implementation of moisture barrier properties andreliability of the element, which is the original function of theencapsulation film.

Also, in the present application, as a result of particle size analysisof the moisture adsorbent for a sample prepared by dissolving theencapsulation layer in an organic solvent and filtering through 300-meshnylon, a ratio of an average particle diameter according to D50 to anaverage particle diameter according to D10 may be in the range of 2.3 to3.5. The lower limit of the ratio may be, for example, 2.4, 2.5, 2.6 or2.7, and the upper limit may be, for example, 3.4, 3.3, 3.2, 3.1, 3.0,2.95 or 2.93. The type of the organic solvent is not particularlylimited, but may be, for example, toluene, and the sample may be onemeasured for a sample cut into, for example, 1.5 cm×1.5 cm. In addition,in this specification, the unit mesh may be a unit of American ASTMstandard. By controlling the particle size distribution, the presentapplication can prevent a decrease in moisture barrier reliability dueto a decrease in dimensional stability at high temperatures, therebyimplementing long-term durability reliability of an organic electronicdevice. The D10 and D50 average particle diameters are valuescorresponding to about 10 weight % and about 50 weight % of the maximumvalue (100 weight %), respectively, in the cumulative distribution graphindicating the weight for each particle diameter.

In one example, the encapsulation layer may further comprise atackifier. The tackifier may be, for example, a compound with asoftening point of 70° C. or higher, where in an embodiment, it may be75° C. or higher, 78° C. or higher, 83° C. or higher, 85° C. or higher,90° C. or higher, or 95° C. or higher, and the upper limit thereof isnot particularly limited, but may be 150° C. or lower, 140° C. or lower,130° C. or lower, 120° C. or lower, 110° C. or lower, or 100° C. orlower. The tackifier may be a compound having a cyclic structure in themolecular structure, where the number of carbon atoms in the cyclicstructure may be in the range of 5 to 15. The number of carbon atoms maybe, for example, in the range of 6 to 14, 7 to 13, or 8 to 12. Thecyclic structure may be a monocyclicstructure, but is not limitedthereto, which may be a bicyclic or tricyclicstructure. The tackifiermay also be an olefin-based polymer, where the polymer may be ahomopolymer or a copolymer. In addition, the tackifier of the presentapplication may be a hydrogenated compound. The hydrogenated compoundmay be a partially or fully hydrogenated compound. Such a tackifier mayhave excellent moisture barrier properties and have external stressrelaxation properties, while having good compatibility with othercomponents in the encapsulation layer. A specific example of thetackifier may include a hydrogenated terpene-based resin, a hydrogenatedester-based resin or a hydrogenated dicyclopentadiene-based resin, andthe like. The weight average molecular weight of the tackifier may be inthe range of about 200 to 5,000 g/mol, 300 to 4,000 g/mol, 400 to 3,000g/mol, or 500 to 2,000 g/mol. The content of the tackifier may beappropriately adjusted as necessary. For example, the content of thetackifier may be included in a ratio of 15 parts by weight to 200 partsby weight, 20 to 190 parts by weight, 25 parts by weight to 180 parts byweight or 30 parts by weight to 150 parts by weight relative to 100parts by weight of the encapsulation resin. The present application canprovide an encapsulation film having excellent moisture barrierproperties and external stress relaxation properties by using thespecific tackifier.

In the encapsulation film of the present application, the encapsulationlayer may comprise a bright spot inhibitor. The bright spot inhibitormay have an adsorption energy of 0 eV or less for outgases, ascalculated by an approximation method of the density functional theory.The lower limit of the adsorption energy is not particularly limited,but may be −20 eV. The type of the outgas is not particularly limited,but may include oxygen, H atoms, H₂ molecules and/or NH₃. As theencapsulation film comprises the bright spot inhibitor, the presentapplication can prevent bright spots due to the outgas generated in theorganic electronic device. In addition, the encapsulation layer of thepresent application comprises the bright spot inhibitor in the secondlayer located on the surface opposite to the element attachment surfaceof the first layer facing the organic electronic element uponencapsulation, whereby the damage to the organic electronic elementaccording to the concentration of stress due to the bright spotinhibitor can be prevented. From such a point of view, the first layermay or may not comprise the bright spot inhibitor in 15% or less basedon the mass of the entire bright spot inhibitor in the encapsulationfilm. In addition, the layer that does not contact the organicelectronic element except for the first layer may comprise 85% or moreof the bright spot inhibitor based on the mass of the entire bright spotinhibitor in the encapsulation film. That is, in the presentapplication, upon element encapsulation, the other encapsulation layerthat does not contact the organic electronic element may contain alarger amount of the bright spot inhibitor compared to the first layerfacing the organic electronic element, whereby it is possible to preventphysical damage to be applied to the element, while implementingmoisture barrier properties and bright spot prevention characteristicsof the film.

In an embodiment of the present application, the adsorption energybetween the bright spot inhibitor and the bright spot-causing atoms ormolecules can be calculated through electronic structure calculationbased on the density functional theory. The above calculation can beperformed by a method known in the art. For example, in the presentapplication, after making a two-dimensional slab structure in which theclosest packed filling surface of a bright spot inhibitor having acrystalline structure is exposed on the surface and then performingstructure optimization, and performing the structure optimization for astructure that the bright spot-causing molecules are adsorbed on thesurface of this vacuum state, the value obtained by subtracting thetotal energy of the bright spot-causing molecules from the total energydifference of these two systems was defined as the adsorption energy.For the total energy calculation about each system, a revised-PBEfunction as a function of GGA (generalized gradient approximation)series was used as exchange-correlation to simulate the interactionbetween electrons and electrons, the used cutoff of the electron kineticenergy was 500 eV and only the gamma point corresponding to the originof the reciprocal space was included and calculated. A conjugategradient method was used to optimize the atomic structure of each systemand iterative calculation was performed until the interatomic force was0.01 eV/A or less. A series of calculation was performed through VASP asa commercially available code.

The material of the bright spot inhibitor is not limited as long as thematerial is a material having the effect of preventing the bright spotson the panel of the organic electronic device when the encapsulationfilm is applied to the organic electronic device. For example, thebright spot inhibitor may be a material capable of adsorbing a materialexemplified by, for example, oxygen, H₂ gas, ammonia (NH₃) gas, H⁺,NH²⁺, NHR₂ or NH₂R as outgas generated from an inorganic depositionlayer of silicon oxide, silicon nitride, or silicon oxynitride depositedon an electrode of an organic electronic element. Here, R may be anorganic group, and for example, may be exemplified by an alkyl group, analkenyl group, an alkynyl group and the like, but is not limitedthereto.

In one example, the material of the bright spot inhibitor is not limitedas long as it satisfies the above adsorption energy value, which may bea metal or a non-metal. The bright spot inhibitor may comprise, forexample, Li, Ni, Ti, Rb, Be, Mg, Ca, Sr, Ba, Al, Zn, In, Pt, Pd, Fe, Cr,Si, or a formulation thereof, may comprise an oxide or a nitride of thematerial, and may comprise an alloy of the material. In one example, thebright spot inhibitor may comprise nickel particles, nickel oxideparticles, titanium nitride, titanium-based alloy particles ofiron-titanium, manganese-based alloy particles of iron-manganese,magnesium-based alloy particles of magnesium-nickel, rare earth-basedalloy particles, zeolite particles, silica particles, carbon nanotubes,graphite, aluminophosphate molecular sieve particles or meso silicaparticles. The bright spot inhibitor may be included in an amount of 3to 150 parts by weight, 6 to 143 parts by weight, 8 to 131 parts byweight, 9 to 123 parts by weight, 10 to 116 parts by weight, 10 parts byweight to 95 parts by weight, 10 parts by weight to 50 parts by weight,or 10 parts by weight to 35 parts by weight, relative to 100 parts byweight of the encapsulation resin. The present application can realizethe bright spot prevention of the organic electronic device whileimproving adhesiveness and durability of the film in the above contentrange. In addition, the bright spot inhibitor may have a particlediameter in a range of 10 nm to 30 μm, 50 nm to 21 μm, 105 nm to 18 μm,110 nm to 12 μm, 120 nm to 9 μm, 140 nm to 4 μm, 150 nm to 2 μm, 180 nmto 900 nm, 230 nm to 700 nm or 270 nm to 400 nm. The particle size maybe according to D50 particle size analysis. By comprising the brightspot inhibitor, the present application can realize moisture barrierproperties and endurance reliability of the encapsulation film togetherwhile efficiently adsorbing hydrogen generated in the organic electronicdevice.

Also, in the present application, as a result of particle size analysisof the moisture adsorbent for a sample filtered through 300-mesh nylonafter dissolving the encapsulation layer in an organic solvent, theratio of the average particle diameter according to D50 to the averageparticle diameter according to D10 may be in the range of 2.3 to 3.5.The lower limit of the ratio may be, for example, 2.4, 2.5, 2.6 or 2.7,and the upper limit may be, for example, 3.4, 3.3, 3.2, 3.1, 3.0, 2.95or 2.93. The type of the organic solvent is not particularly limited,but may be, for example, toluene, and the sample may be one measured fora sample cut into, for example, 1.5 cm×1.5 cm. In addition, in thisspecification, the unit mesh may be a unit of American ASTM standard. Bycontrolling the particle size distribution, the present application canprevent a decrease in moisture barrier reliability due to a decrease indimensional stability at high temperatures, thereby implementinglong-term durability reliability of an organic electronic device.

In one example, the ratio of the particle diameter of the bright spotinhibitor to the particle diameter of the moisture adsorbent may be 2.0or less. The ratio of the particle diameter may be according to the D50particle size analysis. The lower limit of the particle diameter ratiomay be 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, or 1.1 or more, and the upperlimit may be 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9 orless. The original purpose of the encapsulation film of the presentapplication was intended to block moisture from the outside, where inorder to solve the other technical problem of hydrogen adsorption, thebright spot inhibitor was newly introduced, but there was a technicalproblem that it was not easy to maintain the original moisture barriereffect while comprising the bright spot inhibitor. The presentapplication implements excellent bright spot prevention performancewhile maintaining the original moisture barrier effect by adjusting theparticle diameter ratio and/or the above-described particle sizedistribution of the moisture adsorbent and the bright spot inhibitor.

In one example, the encapsulation layer of the present application mayhave a single layer or a multilayer structure comprising at least two ormore encapsulation layers. In the case of comprising the two or moreencapsulation layers, the encapsulation layer may comprise a first layerfacing the organic electronic element when the element is encapsulated,and a second layer located on the surface opposite to the surface of thefirst layer facing the element. In one embodiment, as shown in (a) ofFIG. 2 above, the encapsulation film comprises at least two or moreencapsulation layers, where the encapsulation layer may comprise thefirst layer (2) facing the organic electronic element upon encapsulationand the second layer (4) not facing the organic electronic element.

As described above, the encapsulation layer (2) may have a single-layerstructure. As shown in (a) of FIG. 1 , the encapsulation layer (4) maycomprise a bright spot inhibitor (3). In addition, as shown in (b) ofFIG. 1 , the encapsulation layer (4) may also comprise a bright spotinhibitor (3) and a moisture adsorbent (5) together.

As described above, the encapsulation layer may have a multilayerstructure of two or more layers. When two or more layers constitute theencapsulation layer, the compositions of the respective layers in theencapsulation layer may be the same or different. In one example, theencapsulation layer may comprise an encapsulation resin and/or amoisture adsorbent, and the encapsulation layer may be apressure-sensitive adhesive layer or an adhesive layer.

As shown in (a) of FIG. 2 , the encapsulation layer (2, 4) may comprisea first layer (2) and a second layer (4), and the second layer (4) ofthe encapsulation layer may comprise a bright spot inhibitor (3). Inaddition, as in (b) of FIG. 2 , the second layer may comprise a brightspot inhibitor (3) and a moisture adsorbent (5) together. However, whenthe encapsulation film is applied on the organic electronic element, thefirst layer (2), which is the encapsulation layer facing the organicelectronic element, may not comprise the bright spot inhibitor and themoisture adsorbent, or even if they are included, may comprise a smallamount of 15% or less or 5% or less, on the basis of the weight of thetotal bright spot inhibitor and moisture adsorbent.

In addition, in one example, the encapsulation layer of the presentapplication may comprise an active energy ray polymerizable compoundwhich is highly compatible with the encapsulation resin and can form aspecific cross-linked structure together with the encapsulation resin.

For example, the encapsulation layer of the present application maycomprise a multifunctional active energy ray-polymerizable compound thatcan be polymerized by irradiation of an active energy ray together withthe encapsulation resin. The active energy ray polymerizable compoundmay mean a compound comprising two or more functional groups capable ofparticipating in polymerization reaction by irradiation of an activeenergy ray, for example, functional groups containing an ethylenicallyunsaturated double bond such as an acryloyl group or a methacryloylgroup, or functional groups such as an epoxy group or an oxetane group.

As the multifunctional active energy ray polymerizable compound, forexample, a multifunctional acrylate (MFA) may be used.

Also, the active energy ray polymerizable compound may be included in anamount of 3 parts by weight to 30 parts by weight, 5 parts by weight to25 parts by weight, 8 parts by weight to 20 parts by weight, 10 parts byweight to 18 parts by weight or 12 parts by weight to 18 parts byweight, relative to 100 parts by weight of the encapsulation resin. Thepresent application provides an encapsulation film having excellentendurance reliability even under severe conditions such as hightemperature and high humidity in the above range.

The multifunctional active energy ray polymerizable compound which canbe polymerized by irradiation of the active energy ray can be usedwithout any limitation. For example, the compound may include1,4-butanediol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate,1,6-hexanediol di(meth)acrylate (HDDA), 1,8-octanediol di(meth)acrylate,1,12-dodecanediol di(meth)acrylate, neopentylglycol di(meth)acrylate,dicyclopentanyl di(meth)acrylate, cyclohexane-1,4-diol di(meth)acrylate,tricyclodecanedimethanol (meth)diacrylate, dimethyloldicyclopentanedi(meth)acrylate, neopentylglycol-modified trimethylol propanedi(meth)acrylate, admantane di(meth)acrylate, trimethylolpropanetri(meth)acrylate (TMPTA), or a mixture thereof.

As the multifunctional active energy ray polymerizable compound, forexample, a compound having a molecular weight of 100 or more and lessthan 1,000 g/mol and containing two or more functional groups may beused. The ring structure included in the multifunctional active energyray polymerizable compound may be any one of a carbocyclic structure ora heterocyclic structure; or a monocyclic or polycyclic structure.

In an embodiment of the present application, the encapsulation layer mayfurther comprise a radical initiator. The radical initiator may be aphotoinitiator or a thermal initiator. The specific kind of thephotoinitiator can be appropriately selected in consideration of curingrate and yellowing possibility, and the like. For example,benzoin-based, hydroxy ketone-based, amino ketone-based or phosphineoxide-based photoinitiators, and the like can be used, and specifically,benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropylether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone,dimethylamino acetophenone, 2,2-dimethoxy-2-phenylacetophenone,2,2-diethoxy-2-phenylacetophenone,2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one,4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl) ketone, benzophenone,p-phenylbenzophenone, 4,4′-diethylaminobenzophenone,diclorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone,2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone,2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone,2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethylketal, p-dimethylaminobenzoic acid ester,oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] and2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and the like can beused.

The radical initiator may be included in a ratio of 0.2 parts by weightto 20 parts by weight, 0.5 to 18 parts by weight, 1 to 15 parts byweight, or 2 parts by weight to 13 parts by weight, relative to 100parts by weight of the active energy ray polymerizable compound. As aresult, the reaction of the active energy ray polymerizable compound canbe effectively induced and deterioration of the physical properties ofthe encapsulation layer composition due to the residual components aftercuring can be also prevented.

In an embodiment of the present application, the encapsulation layer ofthe encapsulation film may further comprise a curing agent, depending onthe type of the included resin component. For example, it may furthercomprise a curing agent capable of reacting with the above-mentionedencapsulation resin to form a cross-linked structure or the like. Inthis specification, the terms encapsulation resin and/or binder resinmay be used in the same sense as the resin component.

The kind of the curing agent may be appropriately selected and useddepending on the type of the resin component or the functional groupcontained in the resin.

In one example, when the resin component is an epoxy resin, the curingagent is a curing agent of the epoxy resin known in the art, and forexample, one or two or more of an amine curing agent, an imidazolecuring agent, a phenol curing agent, a phosphorus curing agent or anacid anhydride curing agent, and the like can be used, without beinglimited thereto.

In one example, as the curing agent, an imidazole compound which issolid at room temperature and has a melting point or a decompositiontemperature of 80° C. or higher can be used. As such a compound, forexample, 2-methylimidazole, 2-heptadecylimidazole, 2-phenylimidazole,2-phenyl-4-methylimidazole or 1-cyanoethyl-2-phenylimidazole, and thelike may be exemplified, but is not limited thereto.

The content of the curing agent may be selected depending on compositionof the composition, for example, the type or ratio of the encapsulationresin. For example, the curing agent may be contained in an amount of 1part by weight to 20 parts by weight, 1 part by weight to 10 parts byweight or 1 part by weight to 5 parts by weight, relative to 100 partsby weight of the resin component. However, the weight ratio can bechanged depending on the type and ratio of the encapsulation resin orthe functional group of the resin, or the cross-linking density to beimplemented, and the like.

When the resin component is a resin which can be cured by irradiation ofthe active energy ray, for example, a cationic photopolymerizationinitiator may be used as the initiator.

As the cationic photopolymerization initiator, ionized cationicinitiators of onium salt organometallic salt series, or nonionizedcationic photopolymerization initiators of organic silane or latentsulfonic acid series can be used. As the initiator of the onium saltseries, diaryliodonium salt, triarylsulfonium salt or aryldiazoniumsalt, and the like can be exemplified, as the initiator of theorganometallic salt series, iron arene and the like can be exemplified,as the initiator of the organosilane series, o-nitrobenzyl triaryl silylether, triaryl silyl peroxide or acyl silane, and the like can beexemplified, and as the initiator of the latent sulfuric acid series,α-sulfonyloxy ketone or α-hydroxymethylbenzoin sulfonate, and the likecan be exemplified, without being limited thereto.

In one example, as the cationic initiator, an ionized cationicphotopolymerization initiator may be used.

The encapsulation layer may also comprise a moisture blocker, ifdesired. In this specification, the term “moisture blocker” may mean amaterial which has free or low reactivity with moisture, but canphysically block or hinder movement of moisture or humidity within thefilm. As the moisture blocker, for example, one or two or more of clay,talc, needle-like silica, plate-like silica, porous silica, zeolite,titania or zirconia can be used. In addition, the moisture blocker canbe surface-treated with an organic modifier or the like to facilitatepenetration of organic substances. As such an organic modifier, forexample, dimethyl benzyl hydrogenated tallow quaternary ammonium,dimethyl hydrogenated tallow quaternary ammonium, methyl tallowbis-2-hydroxyethyl quaternary ammonium, dimethyl hydrogenated tallow2-ethylhexyl quaternary ammonium, dimethyl dehydrogenated tallowquaternary ammonium or a mixture thereof, and the like can be used.

The content of the moisture blocker is not particularly limited and maybe suitably selected in consideration of the desired blockingcharacteristics.

In addition to the above-described constitutions, the encapsulationlayer may comprise various additives depending on applications and themanufacturing process of the encapsulation film to be described below.For example, the encapsulation layer may comprise a curable material, across-linking agent, a filler or the like in an appropriate range ofcontent depending on the intended physical properties.

When the encapsulation layer is formed of two or more layers, the secondlayer that does not contact the organic electronic element may comprisethe moisture adsorbent. For example, when it is formed of two or morelayers, the layer in contact with the organic electronic element amongthe encapsulation layer may comprise no moisture adsorbent, or comprisethe moisture adsorbent in a small amount of less than 5 parts by weightor less than 4 parts by weight relative to 100 parts by weight of theencapsulation resin.

Specifically, considering that the encapsulation film is applied toencapsulation of an organic electronic element, the content of themoisture adsorbent can be controlled in consideration of the damage ofthe element. For example, the first layer facing the element uponencapsulation may be comprised of a small amount of a moistureadsorbent, or comprise no moisture adsorbent. In one example, the firstlayer of the encapsulation layer facing the element upon encapsulationmay comprise 0 to 20% of a moisture adsorbent relative to the total massof the moisture adsorbent contained in the encapsulation film. Inaddition, the encapsulation layer that does not contact the element maycomprise 80 to 100% of a moisture adsorbent relative to the total massof the moisture adsorbent contained in the encapsulation film.

In an embodiment of the present application, the encapsulation film mayfurther comprise a metal layer formed on the encapsulation layer. Themetal layer of the present application may have thermal conductivity of20 W/m K or more, 50 W/m K or more, 60 W/m K or more, 70 W/m K or more,80 W/m K or more, 90 W/m K or more, 100 W/m K or more, 110 W/m·K ormore, 120 W/m·K or more, 130 W/m·K or more, 140 W/m·K or more, 150 W/m·Kor more, 200 W/m·K or more, or 210 W/m·K or more. The upper limit of thethermal conductivity is not particularly limited, which may be 800 W/m·Kor less. By having such high thermal conductivity, the heat generated atthe bonding interface upon the metal layer bonding process can bereleased more quickly. Also, the heat accumulated during the operationof the organic electronic device is rapidly released because of the highthermal conductivity, whereby the temperature of the organic electronicdevice itself can be kept lower, and the occurrence of cracks anddefects is reduced. The thermal conductivity may be measured at anytemperature in the temperature range of 15 to 30° C.

The term “thermal conductivity” herein is a degree representingcapability in which a material is capable of transferring heat byconduction, where the unit may be expressed by W/m·K. The unitrepresents the degree to which the material transfers heat at the sametemperature and distance, which means a unit of heat (watt) to a unit ofdistance (meter) and a unit of temperature (kellvin).

In an embodiment of the present application, the metal layer of theencapsulation film may be transparent or opaque. The metal layer mayhave a thickness in a range of 3 μm to 200 μm, 10 μm to 100 μm, 20 μm to90 μm, 30 μm to 80 μm, or 40 μm to 75 μm. The present application canprovide a thin film encapsulation film while realizing sufficient heatrelease effect by controlling the thickness of the metal layer. Themetal layer may be a thin metal foil or a polymer base layer depositedwith metal. The metal layer is not particularly limited as long as it isa material satisfying the above-described thermal conductivity andcontaining a metal. The metal layer may comprise any one from a metal, ametal oxide, a metal nitride, a metal carbide, a metal oxynitride, ametal oxyboride, and a formulation thereof. For example, the metal layermay comprise an alloy in which one or more metal elements or nonmetalelements are added to one metal, and may comprise, for example,stainless steel (SUS). In addition, in one example, the metal layer maycomprise iron, chromium, copper, aluminum, nickel, iron oxide, chromiumoxide, silicon oxide, aluminum oxide, titanium oxide, indium oxide, tinoxide, indium tin oxide, tantalum oxide, zirconium oxide, niobium oxideand a formulation thereof. The metal layer may be deposited by means ofelectrolysis, rolling, thermal evaporation, electron beam evaporation,sputtering, reactive sputtering, chemical vapor deposition, plasmachemical vapor deposition or electron cyclotron resonance source plasmachemical vapor deposition. In one example of the present application,the metal layer may be deposited by reactive sputtering.

Conventionally, a nickel-iron alloy (invar) was usually used as anencapsulation film, but the nickel-iron alloy has a disadvantage thatits price is high, its thermal conductivity is low, and its cuttingproperty is poor. The present application provides an encapsulation filmthat prevents generation of bright spots of organic electronic devices,has excellent heat release characteristics, and implements processconvenience due to magnetism, without using the nickel-iron alloy as themetal layer.

In one example, the metal layer may have a CTE in the range of 2 to 25ppm/K, 4 to 20 ppm/K, 6 to 15 ppm/K, or 9 to 12 ppm/K. In addition, aswill be described below, in the encapsulation film of the presentapplication, the encapsulation layer may encapsulate the top surface ofthe organic electronic element on the substrate. The substrate may havea CTE in the range of 1 to 6 ppm/K, 2 to 5 ppm/K, or 3 to 4 ppm/K. Whenthe encapsulation film encapsulates an organic electronic element, asubstrate, an organic electronic element, an encapsulation layer forencapsulating the organic electronic element and a metal layer on theencapsulation layer are laminated in this order. In this case, thermalexpansion properties between the substrate and the metal layer may bedifferent.

The encapsulation film may further comprise a base film or a releasefilm (hereinafter, may be referred to as a “first film”), which may havea structure in which the encapsulation layer is formed on the base orrelease film. Also, the structure may further comprise a base film, aprotective film or a release film (hereinafter, may be referred to as a“second film”) formed on the metal layer.

The specific kind of the first film that can be used in the presentapplication is not particularly limited. In the present application, forexample, a general polymer film in this field can be used as the firstfilm. In the present application, for example, as the base or releasefilm, a polyethylene terephthalate film, a polytetrafluoroethylene film,a polyethylene film, a polypropylene film, a polybutene film, apolybutadiene film, a polyvinyl chloride film, a polyurethane film, anethylene-vinyl acetate film, an ethylene-propylene copolymer film, anethylene-ethyl acrylate copolymer film, an ethylene-methyl acrylatecopolymer film or a polyimide film, and the like can be used. Inaddition, a suitable mold release treatment may be performed on one sideor both sides of the base film or release film of the presentapplication. As an example of the releasing agent used in the releasingtreatment of the base film, alkyd series, silicone series, fluorineseries, unsaturated ester series, polyolefin series or wax series, andthe like can be used, and among them, a releasing agent of alkyd series,silicone series or fluorine series is preferably used in terms of heatresistance, without being limited thereto.

In the present application, the thickness of the base film or releasefilm (first film) as above is not particularly limited, which may beappropriately selected depending on the application to which it isapplied. For example, in the present application, the thickness of thefirst film may be 10 μm to 500 μm, preferably, 20 μm to 200 μm or so. Ifthe thickness is less than 10 μm, deformation of the base film mayeasily occur during the manufacturing process, whereas if it exceeds 500μm, the economic efficiency is low.

The thickness of the encapsulation layer included in the encapsulationfilm of the present application is not particularly limited, which maybe appropriately selected in accordance with the following conditions inconsideration of the application to which the film is applied. Thethickness of the encapsulation layer may be 5 μm to 200 μm, preferably,5 μm to 100 μm or so. The thickness of the encapsulation layer may bethe entire thickness of the multi-layered encapsulation layer. If thethickness of the encapsulation layer is less than 5 μm, sufficientmoisture barrier ability cannot be exhibited, whereas if it exceeds 200μm, it is difficult to secure processability, the thickness expansiondue to moisture reactivity is large, so that the deposited film of theorganic light emitting element may be damaged, and the economicefficiency is low.

The present application also relates to an organic electronic device. Asshown in FIG. 3 , the organic electronic device may comprise a substrate(21); an organic electronic element (22) formed on the substrate (21);and the above-described encapsulation film (10) for encapsulating theorganic electronic element (22). The encapsulation film may encapsulatethe top surface, for example, all the upper part and the side surface,of the organic electronic element formed on the substrate. Theencapsulation film may comprise an encapsulation layer containing apressure-sensitive adhesive composition or an adhesive composition in across-linked or cured state. Furthermore, the organic electronic devicemay be formed by sealing the encapsulation layer so as to contact thetop surface of the organic electronic element formed on the substrate.

The encapsulation layer for encapsulating the top surface of the organicelectronic element is disposed between the substrate on which theelement is formed and the metal layer of the encapsulation film.However, the materials of the substrate and the metal layer aredifferent from each other and accordingly, the thermal expansioncharacteristics are also different, so that when the organic electronicdevice is present at a high temperature for a certain period of time, adimensional mismatch may occur due to the difference in the degree ofexpansion between the substrate and the metal layer.

When a CTE mismatch occurs between the metal layer and the substrate inthe organic electronic device, as shown in FIG. 4 , a displacementdifference in the substrate (21) and the metal layer (13) of the organicelectronic device occurs, whereby the encapsulation layer (11) laminatedbetween the substrate (21) and the metal layer (13) may be stretched.

In the present application, by adjusting the content of the moistureadsorbent included in the encapsulation layer (11) below in the rangeaccording to General Formula 1 below, the encapsulation layer (11)absorbs or disperses the stress well even between the substrate (21) andthe metal layer (13) at high temperatures. Therefore, it can preventgaps or voids on the side of the encapsulation layer (11), andeffectively prevent foreign substances from penetrating from the outsidewhile having excellent moisture barrier properties. The content of themoisture adsorbent may be in a range such that γ satisfies 0.04 to 0.08in the following general formula 1.Moisture adsorbent content=Q _(MAX)×(H _(T1) +H _(T2)×γ)H_(T1)  [General Formula 1]

In General Formula 1 above, Q_(MAX) is 60 to 90 parts by weight relativeto 100 parts by weight of the solid content of the encapsulation layer,H_(T1) is a thickness of the encapsulation layer at 25° C., H_(T2) is alength of the encapsulation layer connecting the outermost side of thesubstrate and the outermost side of the metal layer at a temperature ofT2, T1 is 25° C., and T2 is 85° C.

In an embodiment of the present application, the organic electronicelement may comprise a pair of electrodes, an organic layer containingat least a light emitting layer, and a passivation film. Specifically,the organic electronic element may comprise a first electrode layer, anorganic layer formed on the first electrode layer and containing atleast a light emitting layer, and a second electrode layer formed on theorganic layer, and may comprise a passivation film for protecting theelectrode on the second electrode layer and the organic layer. The firstelectrode layer may be a transparent electrode layer or a reflectiveelectrode layer, and the second electrode layer may also be atransparent electrode layer or a reflective electrode layer. Morespecifically, the organic electronic element may comprise a transparentelectrode layer formed on a substrate, an organic layer formed on thetransparent electrode layer and containing at least a light emittinglayer, and a reflective electrode layer formed on the organic layer.

Here, the organic electronic element may be, for example, an organiclight emitting element.

The passivation film may comprise an inorganic film and an organic film.In one embodiment, the inorganic film may be metal oxides or nitridesone or more selected from the group consisting of Al, Zr, Ti, Hf, Ta,In, Sn, Zn and Si. The inorganic film may have a thickness of 0.01 μm to50 μm or 0.1 μm to 20 μm or 1 μm to 10 μm. In one example, the inorganicfilm of the present application may be an inorganic material containingno dopant, or may be an inorganic material containing a dopant. Thedopant which can be doped may be one or more elements selected from thegroup consisting of Ga, Si, Ge, Al, Sn, Ge, B, In, Tl, Sc, V, Cr, Mn,Fe, Co and Ni, or an oxide of the element, but is not limited thereto.The organic film is distinguished from the organic layer containing atleast a light emitting layer in that it does not include a lightemitting layer, and may be an organic deposition layer containing anepoxy compound.

The inorganic film or the organic film may be formed by chemical vapordeposition (CVD). For example, as the inorganic film, silicon nitride(SiNx) may be used. In one example, silicon nitride (SiNx) used as theinorganic film may be deposited to a thickness of 0.01 μm to 50 μm. Inone example, the organic film may have a thickness in a range of 2 μm to20 μm, 2.5 μm to 15 μm, or 2.8 μm to 9 μm.

The present application also provides a method for manufacturing anorganic electronic device. The manufacturing method may comprise a stepof applying the above-described encapsulation film to a substrate, onwhich an organic electronic element is formed, so as to cover theorganic electronic element. In addition, the manufacturing method maycomprise a step of curing the encapsulation film. The curing step of theencapsulation film may mean curing of the encapsulation layer, which mayproceed before or after the encapsulation film covers the organicelectronic element.

In this specification, the term “curing” may mean that thepressure-sensitive adhesive composition of the present disclosure formsa cross-linked structure through heating or UV irradiation processes,and the like to be produced in the form of a pressure-sensitiveadhesive. Alternatively, it may mean that the adhesive composition issolidified and attached as an adhesive.

Specifically, the organic electronic element may be formed by forming atransparent electrode on a glass or polymer film used as a substrate bya method such as vacuum evaporation or sputtering, forming a luminescentorganic material layer composed of, for example, a hole transportinglayer, a light emitting layer and an electron transporting layer, andthe like on the transparent electrode, and then further forming anelectrode layer thereon. Subsequently, the encapsulation layer of theencapsulation film is placed to cover the top surface of the organicelectronic element of the substrate subjected to the above process.

Advantageous Effects

The encapsulation film of the present application can be applied tosealing or encapsulation of organic electronic devices such as OLEDs.The film provides an encapsulation film having excellent reliabilitythat allows forming a structure capable of blocking moisture or oxygenflowing into an organic electronic device from the outside, and absorbsand disperses the stress caused by panel bending, while preventinggeneration of bright spots in the organic electronic device.

DESCRIPTION OF DRAWINGS

FIGS. 1 and 2 are cross-sectional diagrams illustrating an encapsulationfilm according to one example of the present application.

FIG. 3 is a cross-sectional diagram illustrating an organic electronicdevice according to one example of the present application.

FIG. 4 is an enlarged cross-sectional diagram of part ‘A’ of FIG. 3 whena CTE mismatch between a metal layer and a substrate occurs in anorganic electronic device.

DETAILED DESCRIPTION

Hereinafter, the present disclosure will be described in more detailthrough examples according to the present disclosure and comparativeexamples not according to the present invention, but the scope of thepresent disclosure is not limited by the following examples.

Example 1

Preparation of Encapsulation Layer

To prepare a first layer solution, a solution (solid content 33%) inwhich a butyl rubber resin (BR068, EXXON) and a tackifier (hydrogenateddicyclopentadiene resin with 9 carbon atoms, softening point: 90° C.,Mw: 570 g/mol) were diluted at a weight ratio (parts by weight) of 50:45with toluene was prepared, and then the solution was homogenized. 5parts by weight of a multifunctional acrylate (HDDA, Miwon) and 1 partby weight of a photoinitiator (Irgacure819, BASF) were introduced to thehomogenized solution and homogenized, and then stirred at high speed for1 hour to prepare a first layer solution.

To prepare a second layer solution, CaO (Sigma-Aldrich, average particlediameter 1 μm) as a moisture adsorbent was prepared as a solution (solidcontent 50%). In addition, separately from this, a solution (solidcontent 50%) in which a butyl rubber resin (BR068, EXXON), Ni particles(particle diameter about 300 nm) as a bright spot inhibitor and atackifier (hydrogenated dicyclopentadiene resin with 9 carbon atoms,softening point: 90° C., Mw: 570 g/mol) were diluted at a weight ratio(parts by weight) of 40:10:55 (butyl rubber: Ni: tackifier) withtoluene, respectively, was prepared, and then the solution washomogenized. 5 parts by weight of a multifunctional acrylate (HDDA,Miwon) and 1 part by weight of a photoinitiator (Irgacure819, BASF) wereintroduced to the homogenized solution and homogenized, and then themoisture adsorbent solution was introduced thereto so that the amount ofthe moisture adsorbent was 100 parts by weight relative to 100 parts byweight of the solid content of the second layer solution, and thenstirred at high speed for 1 hour to prepare a second layer solution.

The encapsulation layer solution as prepared above was separatelyapplied to the release surface of the release PET using a comma coaterfor the first layer and the second layer, respectively, dried in a dryerat 130° C. for 3 minutes to form an encapsulation layer with a firstlayer thickness of 10 μm and a second layer thickness of 50 μm, and thentwo layers were laminated.

Production of Encapsulation Film

On the metal layer (SUS430, thickness 70 μm) prepared in advance, therelease-treated PET attached to the second layer of the encapsulationlayer was peeled off and laminated at 70° C. by a roll-to-roll process,whereby an encapsulation film was produced so that the second layer wasin contact with the metal layer.

The produced encapsulation film was cut to produce an encapsulation filmfor an organic electronic element. The physical properties of the sampleobtained by irradiating the produced film with ultraviolet rays at 2J/cm² are measured.

Example 2

An encapsulation film for an organic electronic device was prepared inthe same manner as in Example 1, except that the CaO dispersion wasintroduced thereto so as to contain 110 parts by weight of CaO as themoisture adsorbent.

Example 3

An encapsulation film for an organic electronic device was prepared inthe same manner as in Example 1, except that the CaO dispersion wasintroduced thereto so as to contain 85 parts by weight of CaO as themoisture adsorbent.

Comparative Example 1

An encapsulation film for an organic electronic device was prepared inthe same manner as in Example 1, except that the CaO dispersion wasintroduced thereto so as to contain 70 parts by weight of CaO as themoisture adsorbent.

Comparative Example 2

An encapsulation film for an organic electronic device was prepared inthe same manner as in Example 1, except that the CaO dispersion wasmixed so as to contain 130 parts by weight of CaO as the moistureadsorbent.

Comparative Example 3

An encapsulation film for an organic electronic device was prepared inthe same manner as in Example 1, except that the CaO dispersion wasmixed so as to contain 140 parts by weight of CaO as the moistureabsorbent.

Experimental Example 1-Calculation of Moisture Adsorbent Content

The encapsulation films prepared in Examples and Comparative Exampleswere each laminated on an encapsulant glass having a CTE_(SUB) of 3.7ppm/K to prepare a frame-shaped sample. In the Examples and ComparativeExamples, the CTE_(METAL) of the metal layer laminated on theencapsulation layer was 10.4 ppm/K.

After the sample was maintained in a constant temperature and humiditychamber at 85° C. and 85% for about 500 hours, any change in the bezelof the frame-type sample was confirmed. At room temperature (25° C.),the thickness (H_(T1)) of the encapsulation layer was 60 μm (thethickness of the first layer 10 μm and the thickness of the second layer50 μm), and the long side length (L_(T1)) of the encapsulation layer was1440 mm.

After 500 hours, the length (H_(T2)) of the encapsulation layerconnecting the outermost side of the encapsulant glass and the outermostside of the metal layer was calculated according to the followinggeneral formula 2.

$\begin{matrix}{\frac{H_{T2}}{H_{T1}} = {\frac{\sqrt{H_{T1}^{2} + {\Delta L_{CTE}^{2}}}}{H_{T1}} \leq 9.}} & {\left\lbrack {{General}{Formula}2} \right\rbrack}\end{matrix}$

In General Formula 2 above, ΔL_(CTE) satisfies the following generalformula 3.ΔL _(CTE)=(CTE _(METAL) −CTE _(SUB))×L _(T1)×(T2−T1)  [General Formula3]

H_(T2) calculated by General Formula 2 above was 296 μm, and themoisture adsorbent content was calculated by substituting the values ofH_(T1) and H_(T2) into the following general formula 1.Moisture adsorbent content=Q _(MAX)×(H _(T1) +H _(T2)×γ)H_(T1)  [General Formula 1]

In General Formula 1 above, Q_(MAX) is 60 to 90 parts by weight relativeto 100 parts by weight of the solid content of the encapsulation layer,and γ is 0.04 to 0.08.

The moisture adsorbent content calculated according to General Formula 1above was confirmed to be 70 to 130 parts by weight relative to thesolid content of the second layer.

Experimental Example 2-Room Temperature Adhesion Test

The adhesion experiment at room temperature was measured based on ASTM3330 using a texture analyzer. The encapsulation films of Examples 1 to3 and Comparative Examples 1 to 3 were each set to a width of 1 inch andstored under 25° C. and 50% relative humidity for 1 hour, and then 1,000gf/inch or more of peel force (peel rate: 5 mm/sec, peel angle: 180°)was measured with respect to a glass substrate (0.5 T).

Experimental Example 3-Reliability Evaluation (Moisture BlockingPerformance)

After depositing an organic electronic element on a 55-inch glasssubstrate (0.5T), the encapsulation films prepared in Examples 1 to 3and Comparative Examples 1 to 3 were laminated on the element underconditions of 25° C., a vacuum degree of 50 mtorr and 0.4 MPa using avacuum bonding machine to produce an organic electronic panel.

While maintaining the produced panel in a constant temperature andhumidity chamber at 85° C. and 85% for about 500 hours, it was observedwhether lifting or bubbles were generated at the interface between theglass substrate and the encapsulation film layer.

When viewed with the naked eye, the case where even one lifting orbubble occurred at the interface between the glass substrate and theencapsulation film layer was denoted as X, and when it did not occur, itwas denoted as O.

Experimental Example 4-Creep Test

In a state where the encapsulation layers of Examples and ComparativeExamples were laminated to a thickness of 600 μm and prepared, avertical force of 200 gf was applied thereto at 85° C. using an 8 mmaluminum parallel plate cell in a Creep mode with ARES (AdvancedRheometric Expansion System), thereby applying a stress of 15,000 Pa tothe film and holding it for 60 seconds, and then the strain value wasmeasured.

TABLE 1 Room temperature Moisture High adhesion blocking temperature(1000 gf/in or more) performance creep (%) Example 1 ◯ ◯ 24 2 ◯ ◯ 21 3 ◯◯ 23 Comparative 1 ◯ X (water 36 Example immersion deterioration) 2 X X(lifting) — 3 X X (lifting) —

DESCRIPTION OF REFERENCE NUMERALS

-   1, 10: encapsulation film-   2, 4, 11: encapsulation layer-   13: metal layer-   3: bright spot inhibitor-   5: moisture adsorbent-   21: substrate-   22: organic electronic element

The invention claimed is:
 1. An encapsulation film comprising: anencapsulation layer which contains an encapsulation resin and a moistureabsorbent and encapsulates the top surface of an organic electronicelement formed on a substrate, and a metal layer formed on theencapsulation layer, wherein content of the moisture adsorbent is in arange such that γ satisfies 0.04 to 0.08 in the following generalformula 1:Moisture adsorbent content=Q _(MAX)×(H _(T1) +H _(T2)×γ)H_(T1)  [General Formula 1] wherein, Q_(MAX) is 60 to 90 parts by weightrelative to 100 parts by weight of the solid content of theencapsulation layer, H_(T1) is a thickness of the encapsulation layer at25° C., H_(T2) is a length of the encapsulation layer connecting theoutermost side of the substrate and the outermost side of the metallayer at a temperature of T2, T1 is 25° C., and T2 is 85° C.
 2. Theencapsulation film according to claim 1, wherein the metal layer has aCTE in a range of 1.5 times or more relative to a CTE of the substrate.3. The encapsulation film according to claim 1, wherein the moistureadsorbent is a chemically reactive adsorbent.
 4. The encapsulation filmaccording to claim 1, wherein as a result of particle size analysis ofthe moisture adsorbent for a sample prepared by dissolving theencapsulation layer in an organic solvent and filtering through 300-meshnylon, a ratio of an average particle diameter according to D50 to anaverage particle diameter according to D10 is in a range of 2.52.3 to3.5.
 5. The encapsulation film according to claim 1, wherein theencapsulation resin has a glass transition temperature of less than 0°C.
 6. The encapsulation film according to claim 1, wherein theencapsulation resin comprises an olefin-based resin.
 7. Theencapsulation film according to claim 1, wherein the encapsulation resincomprises a copolymer of a diene and an olefinic compound containing onecarbon-carbon double bond.
 8. The encapsulation film according to claim1, wherein the encapsulation resin is included in the encapsulationlayer in an amount of 40 wt % or more.
 9. The encapsulation filmaccording to claim 1, wherein the encapsulation layer further comprisesa tackifier.
 10. The encapsulation film according to claim 9, whereinthe tackifier has a softening point of 70° C. or higher.
 11. Theencapsulation film according to claim 9, wherein the tackifier is acompound comprising a cyclic structure having 5 to 15 carbon atoms. 12.The encapsulation film according to claim 9, wherein the tackifier is ahydrogenated compound.
 13. The encapsulation film according to claim 11,wherein the cyclic structure is a bicyclic or tricyclic structure. 14.The encapsulation film according to claim 9, wherein the tackifier isincluded in a range of 15 to 200 parts by weight relative to 100 partsby weight of the encapsulation resin.
 15. The encapsulation filmaccording to claim 1, wherein the encapsulation layer further comprisesa bright spot inhibitor.
 16. The encapsulation film according to claim15, wherein the bright spot inhibitor has an adsorption energy of 0 eVor less for outgases, as calculated by an approximation method of thedensity functional theory.
 17. The encapsulation film according to claim15, wherein the bright spot inhibitor is contained in an amount of 3 to150 parts by weight relative to 100 parts by weight of the encapsulationresin.
 18. The encapsulation film according to claim 1, wherein theencapsulation layer further comprises an active energy ray polymerizablecompound.
 19. An organic electronic device comprising: a substrate; anorganic electronic element formed on the substrate; and theencapsulation film according to claim 1 which encapsulates the organicelectronic element.
 20. A method for manufacturing an organic electronicdevice comprising a step of applying the encapsulation film according toclaim 1 to a substrate on which an organic electronic element is formedso as to cover the organic electronic element.